The world’s largest burger chain announced Wednesday that it will transition to a fully cage-free egg supply for its 16,000 restaurants in the United States and Canada by 2025. Annually, McDonald’s buys approximately 2 billion eggs for its US restaurants and 120 million for its Canada locations, according to a company press release. Of those, just 13 million are cage-free, meaning the supply overhaul will be substantial.

“Our customers are increasingly interested in knowing more about their food and where it comes from,” McDonald’s USA president Mike Andreas said in a statement. “Our decision to source only cage-free eggs reinforces the focus we place on food quality and our menu to meet and exceed our customers’ expectations.”

Transitioning to cage-free eggs, and away from eggs produced by hens in tightly-packed, wire battery cages (as most were for nearly half a century), is quickly becoming standard practice in the US food industry. But the change has been a long time coming. Animal welfare activists and public health experts have long criticized the use of battery cages for being inhumane for the hens and too conducive to spreading filth and disease. Many European countries began phasing them out in the 1990s; the EU banned them outright in 2012.

With a few exceptions, legislative measures in the United States have been less successful. Instead, private companies have spearheaded reforms, prompted by increased consumer awareness of where their food comes from and what goes into it. In July, General Mills, one of the largest food processors in the world, announced that it would be going cage-free, though it didn’t set a timeline. Wal-Mart, Kellogg, Nestlé, Burger King, Starbucks, and Dunkin’ Brands have also signed pledges to eliminate battery cages from their supply chains.

McDonald’s making the switch, however, could be the final death knell for battery cages in the US. The chain is already one of the country’s biggest commercial egg-buyers, and breakfast has been a bright spot as the company’s sales have lagged in recent years. The introduction of all-day breakfast will increase the company’s demand for eggs even more. As with its switch to poultry raised without certain types of antibiotics, the sheer purchasing power of a mega corporation like McDonald’s will likely prompt the nation’s egg farmers to fall in line and create a ripple effect that will make it more affordable for smaller businesses that want to make the cage-free transition.

“McDonald’s admirable move makes clear that egg production's future is cage-free,” Humane Society president Wayne Pacelle said in a statement. “We’re optimistic that the switch can occur even quicker, and we look forward to working with other food companies to follow suit.”

Still, the McDonald’s announcement raises its fair share of questions. As many critics have pointed out over the years, “cage-free” doesn’t necessarily mean free of overcrowding; hens could still be housed, in cramped, dark warehouses and subject to other cruelties, including beak removal.

On the economic end, the US is in the middle of a serious egg crunch, with prices rising and supply dwindling in the wake of a severe bird flu outbreak. With McDonald’s all-day breakfast certain to strain supplies even further, its unclear whether the industry can withstand further short-term disruptions.

On the other hand, that could make it an ideal time for transition, Mr. Paycelle has said. “As the egg industry considers its production strategies in light of the impact of bird flu on cage confinement facilities, there’s an opportunity for the industry to pivot away from caging hens altogether and make the transition to higher-welfare, cage-free systems,” he wrote following General Mills’ cage-free announcement.